In this thesis, the sulfuric and hydrochloric acid leaching of waste lithium-ion-batteries scrap with a concentration of 0.1 mol/l, 1 mol/l and 2 mol/l at a temperature of 60 °C, a leaching time of one hour and a solid-liquid ratio of 1:10 was investigated. Furthermore, the influence of the addition of hydrogen peroxide in a concentration of 5 percent by volume was examined. To analyze the suitability of waste acids for the leaching process, 2 mass percent aluminum, 1 mass percent chromium, 2 mass percent iron, 1 mass percent manganese or 2 mass percent copper (based on the mass of acid used) were added to each acid at a concentration of 2 mol/l and unchanged test conditions. It was found that using both acids (concentration of 2 mol/l) and an NCA material (LiNiCoAlO2) leads to a recovery of over 90 percent of lithium, nickel and cobalt in the filtrate. Furthermore, it was observed that copper only dissolves when hydrogen peroxide is used. The addition of above-mentioned metals had no effect on the leaching characteristics of nickel, cobalt, copper, aluminum or lithium. Therefore, the results of this work show that waste acids contaminated with aluminum, chromium, copper, iron or manganese are basically suitable for the hydrometallurgical recycling of spent lithium-ion batteries.